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Jeremy, Certified Truck/Bus Technician
Category: Medium and Heavy Trucks
Satisfied Customers: 2784
Experience:  ASE Med/HD Truck Technician, NATEF Diesel Engines and Electrical/Electronics Technician, EPA 608/609 HVAC Certified, Steering/Suspension and ABS/Brakes Technician
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I have a Volvo VNL670 blower doesn't engage when truck is in

Customer Question

Hello sir I have a Volvo VNL670 blower doesn't engage when truck is in idle and when it runs it turns on where is the blower located at and what can be the issue here it's. 2009
Submitted: 21 days ago.
Category: Medium and Heavy Trucks
Expert:  Jeremy replied 21 days ago.

My name is ***** ***** I will assist you with your question today.

I'm an independent contractor and I don't get paid until a rating has been made.

We can go back and forth as needed to help resolve the issue you are having. Follow ups are free after ratings, so rate in confidence!

Do you have any A/C codes on the dash? Alternator working properly? Have you tried a new blower motor on this yet?

Sounds like there is a voltage issue getting to the blower motor from the alternator or the voltage regulator, which is in the alternator. The only time I have had a fan do that it wasn;t the fan, it was the alternator not supplying enough power to the cab of the truck and the blower was shut down for protection of the truck to kep the engine running. I know it sounds weird, but these systems are module controlled and that is what it di with me. Check the alternator output first and rule it out.


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Customer: replied 21 days ago.
Ok how much does my alternator to be putting out
Customer: replied 21 days ago.
I'm getting 13.9 V from the alternator the blower hasn't turned on
Expert:  Jeremy replied 21 days ago.

Hmmm... Do you have any codes for the A/C on the dash from the module at all?

Your alternator is putting out the right voltage.

If you rev the engine, the blower comes on or after you start driving? What if you tap the motor on the side, will it engage then while idling?

Customer: replied 21 days ago.
Where is this motor located and I will check the dash again
Expert:  Jeremy replied 21 days ago.

Right side in the dash.

Customer: replied 21 days ago.
inside glove compartment?
Expert:  Jeremy replied 21 days ago.

Yes, behind it.

Customer: replied 20 days ago.
No codes on there Dash
Customer: replied 20 days ago.
it still turns on only when the truck drives what can it possibly be the voltage is good there is no problem with that
Expert:  Jeremy replied 19 days ago.

The only other areas it could be would be the head unit itself (which is what controls the whol AC system aka the knobs) or the relay under the top center of the dash. With no codes, there are no elctrical faults being detected. The blower motor can be faulting, but that is certainly a weird issue to not have faults or voltage issues...

Expert:  Jeremy replied 7 days ago.

I see you viewed this and this is still showing as an open question due to no positive (3 stars or more) rating.

Were you not pleased with my service to you or is there a rating issue? Please let me know if you still need assistance with this, if there is a rating issue, and/or you need more time to respond.

I like to make sure all my customers are satisfied since you did pay a deposit for me to assist you, whether I’m paid by a positive rating feedback or not.

We can continue where we left off or start over if needed. Also, if you need diagrams, instructions, etc please don’t hesitate to ask.

Customer: replied 6 days ago.
I have not had truck in to continue with this issue
Expert:  Jeremy replied 5 days ago.

I was following up because the question timed out on me where I won't see the replies because there were no ratings made. It is treated like the question was abandoned and I wanted to follow up to make sure it was still active for when ready to continue.